Previous fluid pressure pumps of the force type were used to draw a hydraulic fluid through a suction valve from a supply tank, and in the case of a reciprocating hydraulic pump, a piston was activated by a cam to pump the fluid under pressure through a pressure valve into a consumption pipe.
A fluid pressure pump of this type is shown and described in West German Preliminary Published Patent DE-OS 28 13 858. This type of fluid pressure pump includes a piston which is under the force of a spring. The spring is situated on the pump chamber side of the piston. Further, the other side of the piston is in sliding contact with the cam. One of the disadvantages of such an arrangement is that the spring is subject to rapid fatigue since it is constantly affected by changing temperatures and varying loads. Thus, such a spring-biased fluid pressure pump is susceptible to early fatigue.